Polarized light microscopy of chemical-vapor-deposition-grown graphene on copper

Linearly polarized light microscopy (PM) revealed that graphene grown by chemical vapor deposition (CVD) on stepped Cu substrate may appear colored. The coloration is associated with the coupling of the light of 450-600 nm into propagating mode in the graphene layer when the electric vector ((E) over right arrow) of polarized light is parallel with the step edges and with the scattering when the (E) over right arrow is normal to the step edges. PM is an inexpensive, fast, and contamination free method to efficiently visualize graphene and to map the step structure of Cu substrates used for large area CVD growth of graphene. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4719205]